PREVENT (Pre-exposure prevention of viral entry) is an Integrated Preclinical/Clinical Program, with the overall goal to provide a comprehensive set of data to facilitate an informed decision on whether the antiviral lectin Griffithsin (GRFT) shoul progress in the topical microbicides pipeline. GRFT has broad-spectrum activity against human immunodeficiency viruses (HIV) types 1 and 2, herpes simplex virus type 2 (HSV-2) and hepatitis C virus (HCV). Our product target is a rectal microbicide gel, containing GRFT as the primary Active Pharmaceutical Ingredient (API). People who practice unprotected receptive anal intercourse (URAI) represent the population most vulnerable to HIV-1 transmission due to the high preponderance of HIV target cells in the rectal mucosa, and mucosal trauma commonly associated with RAI. As a small protein, unlikely to be widely used in antiretroviral therapy, the GRFT PREVENT program stands apart from pre-exposure prophylaxis (PREP) strategies that involve small molecule antiretrovirals (ARV), which bear the potential risk of selecting for viral resistance. Broad spectrum antiviral prophylaxis that is offered by lubricant gels containing GRFT offer a much needed option for HIV infected people who require effective PREP against superinfection with HIV as well as HSV-2, HCV and other enveloped viruses that are transmitted by URAI. Three Projects and four Cores will all contribute to the Specific Aims of the Overall Program. Aim 1: Provide a comprehensive set of safety and efficacy data to facilitate a Go/No-Go decision on progression of GRFT rectal microbicides into later stage clinical studies. Aim 2: Manage and integrate the PREVENT U19 Program with the goals and expectations of the NIH sponsor and future sponsors and investors in GRFT microbicide gel products.